JD820 Fuel injection pump

I have a JD820 tractor that I am somewhat restoring. The motor is rebuilt and I haev started it. The problem: The fuel injection pump (Roosa MAster Model CBC331-4AL) leaks where the governor goes into the pump. The parts (JD) diagram for this shows one o-ring where the governor goes into the pump. There are three actual grooves on the governor shaft and I am now not sure which groove the o-ring should go on. Does anyone have knowledge about this pump or possibly a better IPB for the pump...better then that shown on JDs web-site? The pump seems to work fine and the tractor runs. I just need to stop this fuel leak! Thanks for any feedback!!!
Dave

Re: JD820 Fuel injection pump

My neighbor has a JD 820 (one of the 3 cylinder 1970ish ones). Some of the men helping her brought over a diesel mechanic. He said her problem was a screw that goes into the side of the injector pump. They diddle with the screw and are able to run the tractor for a while, but it eventually quits.

So, I'd like to know more about these injector pumps as well.

Previously, I replaced the fuel filters and little pump that supplies the filters and injector. It was then that she brought these other guys in. She didn't want to pay the local dealer to come get it and looked at by their mechanics.

Re: JD820 Fuel injection pump

I have had this pump out numerous times, I do know about this screw...as a matter of fact, the one on the pump I have broke (I broke the tip off that goes into the sleeve. I made another one. It is a potential leaking area. If this screw goes in to far it could potentially stop the valve from moving and thus not allow the tractor to start...no fuel! Also the gears on the rod can strip...I had this problem, so no fuel. These I have replaced...$65 for both. JD parts web-site does have diagram of the pump but they do not seem to be able to get many parts and do not work on them. They refer one to a diesel service place.